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7.3
Pypdf Library Can Fail to Process Large PDF Files
CVE-2026-27025
GHSA-wgvp-vg3v-2xq3
CVE-2026-27025
Summary
The pypdf library may take a long time or use a lot of memory when processing certain large PDF files. This could cause delays or crashes. Update to the latest version, pypdf 6.7.1, to prevent this issue.
What to do
- Update pypdf to version 6.7.1.
Affected software
| Vendor | Product | Affected versions | Fix available |
|---|---|---|---|
| – | pypdf | <= 6.7.1 | 6.7.1 |
| pypdf_project | pypdf | <= 6.7.1 | – |
Original title
pypdf has possible long runtimes/large memory usage for large /ToUnicode streams
Original description
pypdf is a free and open-source pure-python PDF library. Prior to 6.7.1, an attacker who uses this vulnerability can craft a PDF which leads to long runtimes and large memory consumption. This requires parsing the /ToUnicode entry of a font with unusually large values, for example during text extraction. This vulnerability is fixed in 6.7.1.
nvd CVSS3.1
5.5
nvd CVSS4.0
6.9
Vulnerability type
CWE-834
- https://nvd.nist.gov/vuln/detail/CVE-2026-27025
- https://github.com/advisories/GHSA-wgvp-vg3v-2xq3
- https://github.com/py-pdf/pypdf/commit/77d7b8d7cfbe8dd179858dfa42666f73fc6e57a2 Patch
- https://github.com/py-pdf/pypdf/pull/3646 Issue Tracking Patch
- https://github.com/py-pdf/pypdf/releases/tag/6.7.1 Product Release Notes
- https://github.com/py-pdf/pypdf/security/advisories/GHSA-wgvp-vg3v-2xq3 Patch Vendor Advisory
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27025... Vendor Advisory
Published: 20 Feb 2026 · Updated: 12 Mar 2026 · First seen: 6 Mar 2026